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Tungu P, Kabula B, Nkya T, Machafuko P, Sambu E, Batengana B, Sudi W, Derua YA, Mwingira V, Masue D, Malima R, Kitojo C, Serbantez N, Reaves EJ, Mwalimu C, Nhiga SL, Ally M, Mkali HR, Joseph JJ, Chan A, Ngondi J, Lalji S, Nyinondi S, Eckert E, Reithinger R, Magesa S, Kisinza WN. Trends of insecticide resistance monitoring in mainland Tanzania, 2004-2020. Malar J 2023; 22:100. [PMID: 36932400 PMCID: PMC10024418 DOI: 10.1186/s12936-023-04508-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/20/2023] [Indexed: 03/19/2023] Open
Abstract
BACKGROUND Insecticide resistance is a serious threat to the continued effectiveness of insecticide-based malaria vector control measures, such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). This paper describes trends and dynamics of insecticide resistance and its underlying mechanisms from annual resistance monitoring surveys on Anopheles gambiae sensu lato (s.l.) populations conducted across mainland Tanzania from 2004 to 2020. METHODS The World Health Organization (WHO) standard protocols were used to assess susceptibility of the wild female An. gambiae s.l. mosquitoes to insecticides, with mosquitoes exposed to diagnostic concentrations of permethrin, deltamethrin, lambdacyhalothrin, bendiocarb, and pirimiphos-methyl. WHO test papers at 5× and 10× the diagnostic concentrations were used to assess the intensity of resistance to pyrethroids; synergist tests using piperonyl butoxide (PBO) were carried out in sites where mosquitoes were found to be resistant to pyrethroids. To estimate insecticide resistance trends from 2004 to 2020, percentage mortalities from each site and time point were aggregated and regression analysis of mortality versus the Julian dates of bioassays was performed. RESULTS Percentage of sites with pyrethroid resistance increased from 0% in 2004 to more than 80% in the 2020, suggesting resistance has been spreading geographically. Results indicate a strong negative association (p = 0.0001) between pyrethroids susceptibility status and survey year. The regression model shows that by 2020 over 40% of An. gambiae mosquitoes survived exposure to pyrethroids at their respective diagnostic doses. A decreasing trend of An. gambiae susceptibility to bendiocarb was observed over time, but this was not statistically significant (p = 0.8413). Anopheles gambiae exhibited high level of susceptibility to the pirimiphos-methyl in sampled sites. CONCLUSIONS Anopheles gambiae Tanzania's major malaria vector, is now resistant to pyrethroids across the country with resistance increasing in prevalence and intensity and has been spreading geographically. This calls for urgent action for efficient malaria vector control tools to sustain the gains obtained in malaria control. Strengthening insecticide resistance monitoring is important for its management through evidence generation for effective malaria vector control decision.
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Affiliation(s)
- Patrick Tungu
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania.
| | - Bilali Kabula
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
- USAID-Okoa Maisha Dhibiti Malaria Project, RTI International, Dar es Salaam, Tanzania
| | - Theresia Nkya
- University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Pendael Machafuko
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Edward Sambu
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Bernard Batengana
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Wema Sudi
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Yahaya A Derua
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Victor Mwingira
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - Denis Masue
- University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Robert Malima
- University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Chonge Kitojo
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, Tanzania
| | - Erik J Reaves
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention, Dar es Salaam, Tanzania
| | - Charles Mwalimu
- National Malaria Control Programme, Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Samwel L Nhiga
- National Malaria Control Programme, Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Mohamed Ally
- National Malaria Control Programme, Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Humphrey R Mkali
- USAID-Okoa Maisha Dhibiti Malaria Project, RTI International, Dar es Salaam, Tanzania
| | - Joseph J Joseph
- USAID-Okoa Maisha Dhibiti Malaria Project, RTI International, Dar es Salaam, Tanzania
| | - Adeline Chan
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention, Atlanta, USA
| | | | - Shabbir Lalji
- USAID-Okoa Maisha Dhibiti Malaria Project, RTI International, Dar es Salaam, Tanzania
| | - Ssanyu Nyinondi
- USAID-Okoa Maisha Dhibiti Malaria Project, RTI International, Dar es Salaam, Tanzania
| | | | | | - Stephen Magesa
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
| | - William N Kisinza
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, Tanzania
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2
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Mandeng SE, Awono-Ambene HP, Bigoga JD, Ekoko WE, Binyang J, Piameu M, Mbakop LR, Fesuh BN, Mvondo N, Tabue R, Nwane P, Mimpfoundi R, Toto JC, Kleinschmidt I, Knox TB, Mnzava AP, Donnelly MJ, Fondjo E, Etang J. Spatial and temporal development of deltamethrin resistance in malaria vectors of the Anopheles gambiae complex from North Cameroon. PLoS One 2019; 14:e0212024. [PMID: 30779799 PMCID: PMC6380565 DOI: 10.1371/journal.pone.0212024] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 01/26/2019] [Indexed: 02/07/2023] Open
Abstract
The effectiveness of insecticide-based malaria vector control interventions in Africa is threatened by the spread and intensification of pyrethroid resistance in targeted mosquito populations. The present study aimed at investigating the temporal and spatial dynamics of deltamethrin resistance in An. gambiae s.l. populations from North Cameroon. Mosquito larvae were collected from 24 settings of the Garoua, Pitoa and Mayo Oulo Health Districts (HDs) from 2011 to 2015. Two to five days old female An. gambiae s.l. emerging from larval collections were tested for deltamethrin resistance using the World Health Organization’s (WHO) standard protocol. Sub samples of test mosquitoes were identified to species using PCR-RFLP and genotyped for knockdown resistance alleles (Kdr 1014F and 1014S) using Hot Ligation Oligonucleotide Assay (HOLA). All the tested mosquitoes were identified as belonging to the An. gambiae complex, including 3 sibling species mostly represented by Anopheles arabiensis (67.6%), followed by Anopheles coluzzii (25.4%) and Anopheles gambiae (7%). Deltamethrin resistance frequencies increased significantly between 2011 and 2015, with mosquito mortality rates declining from 70–85% to 49–73% in the three HDs (Jonckheere-Terstra test statistic (JT) = 5638, P< 0.001), although a temporary increase of mortality rates (91–97%) was seen in the Pitoa and Mayo Oulo HDs in 2012. Overall, confirmed resistance emerged in 10 An. gambiae s.l. populations over the 24 field populations monitored during the study period, from 2011 to 2015. Phenotypic resistance was mostly found in urban settings compared with semi-urban and rural settings (JT = 5282, P< 0.0001), with a spatial autocorrelation between neighboring localities. The Kdr 1014F allelic frequencies in study HDs increased from 0–30% in 2011 to 18–61% in 2014–2015 (JT = 620, P <0.001), especially in An. coluzzii samples. The overall frequency of the Kdr 1014S allele was 0.1%. This study revealed a rapid increase and widespread deltamethrin resistance frequency as well as Kdr 1014F allelic frequencies in An. gambiae s.l. populations over time, emphasizing the urgent need for vector surveillance and insecticide resistance management strategies in Cameroon.
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Affiliation(s)
- Stanislas Elysée Mandeng
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Laboratory of General Biology, University of Yaounde I, Yaounde, Cameroon
| | - Herman Parfait Awono-Ambene
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Jude D. Bigoga
- Laboratory for Vector Biology and control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, Yaounde, Cameroon
| | - Wolfgang Eyisap Ekoko
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Laboratory of Animal Biology and Physiology, Faculty of Science, University of Douala, Douala, Cameroon
| | - Jérome Binyang
- Laboratory of General Biology, University of Yaounde I, Yaounde, Cameroon
| | - Michael Piameu
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Ecole des Sciences de la Santé, Université Catholique d’Afrique Centrale, Yaoundé, Cameroon
| | - Lili Ranaise Mbakop
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Laboratory of General Biology, University of Yaounde I, Yaounde, Cameroon
| | - Betrand Nono Fesuh
- National Advanced School of Engineering, University of Yaounde I, Yaounde, Cameroon
| | - Narcisse Mvondo
- Laboratory of General Biology, University of Yaounde I, Yaounde, Cameroon
| | - Raymond Tabue
- Laboratory for Vector Biology and control, National Reference Unit for Vector Control, The Biotechnology Center, Nkolbisson-University of Yaounde I, Yaounde, Cameroon
- Ministry of Public Health, National Malaria Control Programme, Yaounde, Cameroon
| | - Philippe Nwane
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Rémy Mimpfoundi
- Laboratory of General Biology, University of Yaounde I, Yaounde, Cameroon
| | - Jean Claude Toto
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | - Immo Kleinschmidt
- Department of Infectious Disease Epidemiology, London School of Tropical Medicine & Hygiene, MRC Tropical Epidemiology Group, London, United Kingdom
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Tessa Bellamy Knox
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | - Martin James Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Etienne Fondjo
- Ministry of Public Health, National Malaria Control Programme, Yaounde, Cameroon
| | - Josiane Etang
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Department of biological sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Institute for Insect Biotechnology, Justus Liebig University Gießen, Heinrich-Buff-Ring, Germany
- * E-mail:
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Chi-Chim WA, Bocanegra-Garcia V, Reyes-Solis G, García-Rejon JE, Baak-Baak CM, Machain-Williams C, Chan-Orilla JA, Gomez-Garcia C, Ballina-Gomez HS, Reyes-Lopez MA. Frequency of the L1014F Mutation in the Sodium Channel Gene, in Culex quinquefasciatus (Diptera: Culicidae) Populations From Rural and Urban Areas of Yucatan State, Mexico. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:1633-1637. [PMID: 30060188 DOI: 10.1093/jme/tjy121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Indexed: 06/08/2023]
Abstract
Culex quinquefasciatus Say (Diptera: Culicidae) is a mosquito species that has attracted a lot of attention from a medical and veterinary point of view; however, little is known about the frequency of L1014F mutations that have been found in the sodium channel gene, with this being a target for DDT and pyrethroid insecticides. The distribution and frequency of the L1014F mutation in Cx. quinquefasciatus populations was determined in rural and urban areas of Yucatan, Mexico from January 2015 to March 2016. Nine hundred fifty adult females out of 17,727 immature states were collected and analyzed in all sites sampled (n = 10). Susceptible homozygotes were identified (L1014/L1014) in 12% (114/950), heterozygous individuals (F1014/L1014) in 34% (323/950), and mutated homozygotes (F1014/F1014) in 54% (513/950) during the dry and rainy seasons. In this work, study areas with a high frequency of L1014F mutation were identified. These findings may help guarantee a more effective and efficient use of the resources available for the control of this vector.
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Affiliation(s)
- Wilbert A Chi-Chim
- Conservation Medicine Lab. Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Blvd. del Maestro S/N esq. Elias Piña, Narcizo Mendoza, Cd. Reynosa, Mexico
| | - Virgilio Bocanegra-Garcia
- Conservation Medicine Lab. Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Blvd. del Maestro S/N esq. Elias Piña, Narcizo Mendoza, Cd. Reynosa, Mexico
| | - Guadalupe Reyes-Solis
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, colonia Inalambrica, Merida, Yucatan, Mexico
| | - Julian E García-Rejon
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, colonia Inalambrica, Merida, Yucatan, Mexico
| | - Carlos M Baak-Baak
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, colonia Inalambrica, Merida, Yucatan, Mexico
| | - Carlos Machain-Williams
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, colonia Inalambrica, Merida, Yucatan, Mexico
| | - Julio A Chan-Orilla
- Laboratorio de Arbovirologia, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, colonia Inalambrica, Merida, Yucatan, Mexico
| | - Consuelo Gomez-Garcia
- Laboratorio de Biomedicina Molecular I. Escuela Nacional de Medicina y Homeopatía del Instituto Politécnico Nacional (ENMyH-IPN), México
| | | | - Miguel Angel Reyes-Lopez
- Conservation Medicine Lab. Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, Blvd. del Maestro S/N esq. Elias Piña, Narcizo Mendoza, Cd. Reynosa, Mexico
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4
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Zoh DD, Ahoua Alou LP, Toure M, Pennetier C, Camara S, Traore DF, Koffi AA, Adja AM, Yapi A, Chandre F. The current insecticide resistance status of Anopheles gambiae (s.l.) (Culicidae) in rural and urban areas of Bouaké, Côte d'Ivoire. Parasit Vectors 2018; 11:118. [PMID: 29499720 PMCID: PMC5834858 DOI: 10.1186/s13071-018-2702-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 02/07/2018] [Indexed: 11/26/2022] Open
Abstract
Background Several studies were carried out in experimental hut station in areas surrounding the city of Bouaké, after the crisis in Côte d’Ivoire. They reported increasing resistance levels to insecticide for malaria transmiting mosquitoes. The present work aims to evaluate the current resistance level of An. gambiae(s.l.) in rural and urban areas in the city of Bouaké. Methods Larvae of Anopheles gambiae (s.l.) were collected from five different study sites and reared to adult stages. The resistance status was assessed using the WHO bioassay test kits for adult mosquitoes, with eight insecticides belonging to pyrethroids, organochlorines, carbamates and organophosphates classes. Molecular assays were performed to identify the molecular forms of An. gambiae (s.l.), the L1014F kdr and the ace-1R alleles in individual mosquitoes. The synergist PBO was used to investigate the role of enzymes in resistance. Biochemical assays were performed to detect potential increased activities in mixed function oxidase (MFO) levels, non-specific esterases (NSE) and glutathione S-transferases (GST). Results High resistance levels to pyrethroids, organochlorines, and carbamates were observed in Anopheles gambiae (s.l.) from Bouaké. Mortalities ranged between 0 and 73% for the eight tested insecticides. The pre-exposure to PBO restored full or partial susceptibility to pyrethroids in the different sites. The same trend was observed with the carbamates in five sites, but to a lesser extent. With DDT, pre-exposure to PBO did not increase the mortality rate of An. gambiae (s.l.) from the same sites. Tolerance to organophosphates was observed. An increased activity of NSE and higher level of MFO were found compared to the Kisumu susceptible reference strain. Two molecular forms, S form [(An. gambiae (s.s)] and M form (An. coluzzi) were identified. The kdr allele frequencies vary from 85.9 to 99.8% for An. gambiae (s.s.) and from 81.7 to 99.6% for An. coluzzii. The ace-1R frequencies vary between 25.6 and 38.8% for An. gambiae (s.s.) and from 28.6 to 36.7% for An. coluzzii. Conclusion Resistance to insecticides is widespread within both An. gambiae (s.s.) and An. coluzzii. Two mechanisms of resistance, i.e. metabolic and target-site mutation seemed to largely explain the high resistance level of mosquitoes in Bouaké. Pyrethroid resistance was found exclusively due to the metabolic mechanism.
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Affiliation(s)
- Dounin Danielle Zoh
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire. .,Université Félix Houphouët Boigny, 08 BP 3800, Abidjan, 08, Côte d'Ivoire.
| | | | - Mahama Toure
- Centre d'Entomologie Médicale et Vétérinaire, 27 BP 529, Abidjan, 27, Côte d'Ivoire
| | - Cédric Pennetier
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire.,MIVEGEC, Institut de Recherche pour le Développement - CNRS - University Montpellier, Délégation Occitanie, 911 Av. Agropolis, Montpellier, France
| | - Soromane Camara
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire.,Université Félix Houphouët Boigny, 08 BP 3800, Abidjan, 08, Côte d'Ivoire
| | - Dipomin François Traore
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire.,Centre d'Entomologie Médicale et Vétérinaire, 27 BP 529, Abidjan, 27, Côte d'Ivoire
| | | | - Akré Maurice Adja
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire.,Université Félix Houphouët Boigny, 08 BP 3800, Abidjan, 08, Côte d'Ivoire
| | - Ahoua Yapi
- Institut Pierre Richet, 01 BP 1500, Bouaké, 01, Côte d'Ivoire
| | - Fabrice Chandre
- MIVEGEC, Institut de Recherche pour le Développement - CNRS - University Montpellier, Délégation Occitanie, 911 Av. Agropolis, Montpellier, France
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Nnko EJ, Kihamia C, Tenu F, Premji Z, Kweka EJ. Insecticide use pattern and phenotypic susceptibility of Anopheles gambiae sensu lato to commonly used insecticides in Lower Moshi, northern Tanzania. BMC Res Notes 2017; 10:443. [PMID: 28877733 PMCID: PMC5585946 DOI: 10.1186/s13104-017-2793-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 08/31/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Evidence of insecticide resistance has been documented in different malaria endemic areas. Surveillance studies to allow prompt investigation of associated factors to enable effective insecticide resistance management are needed. The objective of this study was to assess insecticide use pattern and phenotypic susceptibility level of Anopheles gambiae sensu lato to insecticides commonly used in malaria control in Moshi, northern Tanzania. METHODS A cross-sectional survey was conducted to assess insecticide usage pattern. Data was collected was through closed and open ended questionnaires The WHO diagnostic standard kit with doses of 0.1% bendiocarb, 0.05% deltamethrin, 0.75% permethrin and 4% DDT were used to detect knockdown time, mortality and resistance ratio of wild A. gambiae sensu lato. The questionnaire survey data was analyzed using descriptive statistics and one-way analysis of variance while susceptibility data was analysed by logistic regression with probit analysis using SPSS program. The WHO criteria was used to evaluate the resistance status of the tested mosquito populations. RESULTS A large proportion of respondents (80.8%) reported to have used insecticide mainly for farming purposes (77.3%). Moreover, 93.3% of household reported usage of long lasting insecticidal nets. The frequently used class of insecticide was organophosphate with chloropyrifos as the main active ingredients and dursban was the brand constantly reported. Very few respondents (24.1%) applied integrated vector control approaches of and this significantly associated with level of knowledge of insecticide use (P < 0.001). Overall knockdown time for A. gambiae s.l was highest in DDT, followed by Pyrethroids (Permethrin and deltamethrin) and lowest in bendiocarb. Anopheles gambiae s.l showed susceptibility to bendiocarb, increased tolerance to permethrin and resistant to deltamethrin. The most effective insecticide against the population from tested was bendiocarb, with a resistance ratio ranging between 0.93-2.81. CONCLUSION Education on integrated vector management should be instituted and a policy change on insecticide of choice for malaria vector control from pyrethroids to carbamates (bendiocarb) is recommended. Furthermore, studies to detect cross resistance between pyrethroids and organophosphates should be carried out.
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Affiliation(s)
- Elinas J. Nnko
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P.O. Box 65011, Dar es Salaam, Tanzania
| | - Charles Kihamia
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P.O. Box 65011, Dar es Salaam, Tanzania
| | - Filemoni Tenu
- National Institute for Medical Research, Amani Medical Research Centre, Muheza, P.O. Box 81, Tanga, Tanzania
| | - Zul Premji
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, P.O. Box 65011, Dar es Salaam, Tanzania
| | - Eliningaya J. Kweka
- Tropical Pesticides Research Institute, Division of Livestock and Human Health Disease Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464 Mwanza, Tanzania
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Niang M, Niass O, Diagne N, Sarr FD, Faye MM, Diop F, Diouf B, Faye J, Badiane A, Perraut R, Sokhna C, Trape JF, Tall A, Toure-Balde A. Temporal analysis of IgG antibody responses to Plasmodium falciparum antigens in relation to changing malaria epidemiology in a West African setting. Malar J 2017; 16:283. [PMID: 28693608 PMCID: PMC5504683 DOI: 10.1186/s12936-017-1928-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/30/2017] [Indexed: 12/02/2022] Open
Abstract
Background Coordinated scaled-up malaria control interventions have substantially contributed to the dramatic decrease of malaria-related morbidity and mortality in several endemic countries, including Senegal. However, the impacts of a given malaria control intervention on vector and parasite populations, acquired immunity, and disease burden remain very poorly documented largely due to the lack of continuous surveys. This study took advantage of the sera bank established as part of the Dielmo longitudinal project to investigate the dynamics of IgG antibody responses that accompanied the epidemiological changes resulting from malaria control interventions. Schizonts crude extract of a local strain of Plasmodium falciparum (Pfsch07/03) was used in ELISA to measure and compare seroprevalence and magnitude of IgG antibody responses from 2000 to 2012. Results The prevalence of Pfsch07/03 IgG antibody responses progressively decreased from 97.25% in 2000 to 57.3% in 2012. The prevalence of Pfsch07/03 antibodies categorized between three different age groups (<7, 7–15, and >15 years) revealed increased seroprevalence with age ranging from 47.19 to 62.67 and 89.45%, respectively in (<7, 7–15, and >15 years) old age groups. A marked drop in seroprevalence was observed after 2008 and was significant in the younger (<7 years) and intermediate (7–15 years) age groups, unlike older individuals aged >15 years (p = 1.00). Conclusions The study revealed a substantial contribution of all malaria control interventions to the decrease of IgG antibodies responses to Pfsch07/03 throughout prevention of human-mosquitos contacts, or reduction of parasite biomass. The present study demonstrates the wider potential of sero-epidemiological analysis in monitoring changes in malaria transmission resulting from a given malaria control intervention.
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Affiliation(s)
- Makhtar Niang
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Oumy Niass
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Nafissatou Diagne
- Institut de Recherche pour le développement, BP 1386, Dakar, Senegal
| | - Fatoumata Diene Sarr
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Michel Matar Faye
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Fode Diop
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Babacar Diouf
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Joseph Faye
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Abdoulaye Badiane
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Ronald Perraut
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Cheikh Sokhna
- Institut de Recherche pour le développement, BP 1386, Dakar, Senegal
| | | | - Adama Tall
- Epidemiology of Infectious Diseases Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal
| | - Aissatou Toure-Balde
- Immunology Unit, Institut Pasteur Dakar, 36 Avenue Pasteur, BP 220, Dakar, Senegal.
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Ponce G, Sanchez IP, García SM, Torrado JM, Lozano-Fuentes S, Lopez-Monroy B, Flores AE. First report of L1014F kdr mutation in Culex quinquefasciatus in Mexico. INSECT SCIENCE 2016; 23:829-834. [PMID: 25765734 DOI: 10.1111/1744-7917.12218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/02/2015] [Indexed: 06/04/2023]
Abstract
The L1014F mutation in the voltage-sodium channel gene has been associated with resistance to DDT and pyrethroids in various arthropod species including mosquitoes. We determined the frequency of the L1014F kdr mutation in 16 field populations of Culex quinquefasciatus from Northeastern Mexico collected between 2008 and 2013. The L1014F was present in all populations analyzed with the lowest frequency (3.33%) corresponding to the population from Monclova collected in 2012, and the highest frequency (63.63%) from the Monterrey population collected in 2012. The presence of a kdr mutation in populations of Cx. quinquefasciatus from northeastern Mexico provides evidence of pyrethroid resistance. This requires a special attention, considering that pyrethroid-based insecticides are commonly used in vector-control campaigns, especially against Aedes aegypti (L.).
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Affiliation(s)
- Gustavo Ponce
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
| | - Iram P Sanchez
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
| | - Selene M García
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
| | - Jose M Torrado
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
| | - Saúl Lozano-Fuentes
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Beatriz Lopez-Monroy
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
| | - Adriana E Flores
- Facultad de Ciencias Biologicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n Cd. Universitaria San Nicolas de los Garza, N.L., 66455, Mexico, USA
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8
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Mzilahowa T, Chiumia M, Mbewe RB, Uzalili VT, Luka-Banda M, Kutengule A, Mathanga DP, Ali D, Chiphwanya J, Zoya J, Mulenga S, Dodoli W, Bergeson-Lockwood J, Troell P, Oyugi J, Lindblade K, Gimnig JE. Increasing insecticide resistance in Anopheles funestus and Anopheles arabiensis in Malawi, 2011-2015. Malar J 2016; 15:563. [PMID: 27876046 PMCID: PMC5120501 DOI: 10.1186/s12936-016-1610-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Susceptibility of principal Anopheles malaria vectors to common insecticides was monitored over a 5-year period across Malawi to inform and guide the national malaria control programme. METHODS Adult blood-fed Anopheles spp. and larvae were collected from multiple sites in sixteen districts across the country between 2011 and 2015. First generation (F1) progeny aged 2-5 days old were tested for susceptibility, using standard WHO procedures, against pyrethroids (permethrin and deltamethrin), carbamates (bendiocarb and propoxur), organophosphates (malathion and pirimiphos-methyl) and an organochlorine (DDT). RESULTS Mortality of Anopheles funestus to deltamethrin, permethrin, bendiocarb and propoxur declined significantly over the 5-year (2011-2015) monitoring period. There was wide variation in susceptibility to DDT but it was not associated with time. In contrast, An. funestus exhibited 100% mortality to the organophosphates (malathion and pirimiphos-methyl) at all sites tested. There was reduced mortality of Anopheles arabiensis to deltamethrin over time though this was not statistically significant. However, mortality of An. arabiensis exposed to permethrin declined significantly over time. Anopheles arabiensis exposed to DDT were more likely to be killed if there was high ITN coverage in the mosquito collection area the previous year. There were no other associations between mosquito mortality in a bioassay and ITN coverage or IRS implementation. Mortality of An. funestus from four sites exposed to deltamethrin alone ranged from 2 to 31% and from 41 to 94% when pre-exposed to the synergist piperonyl butoxide followed by deltamethrin. For permethrin alone, mortality ranged from 2 to 13% while mortality ranged from 63 to 100% when pre-exposed to PBO. CONCLUSION Pyrethroid resistance was detected in An. funestus and An. arabiensis populations across Malawi and has worsened over the last 5 years. New insecticides and control strategies are urgently needed to reduce the burden of malaria in Malawi.
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Affiliation(s)
- Themba Mzilahowa
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi.
| | - Martin Chiumia
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Rex B Mbewe
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Veronica T Uzalili
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Madalitso Luka-Banda
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Anna Kutengule
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Don P Mathanga
- Malaria Alert Centre, Malawi College of Medicine, Chichiri, P/Bag 360, Blantyre 3, Malawi
| | - Doreen Ali
- Community Health Services Unit, National Malaria Control Programme, Ministry of Health, Lilongwe, Malawi
| | - John Chiphwanya
- Community Health Services Unit, National Malaria Control Programme, Ministry of Health, Lilongwe, Malawi
| | - John Zoya
- Community Health Services Unit, National Malaria Control Programme, Ministry of Health, Lilongwe, Malawi
| | - Shadreck Mulenga
- Community Health Services Unit, National Malaria Control Programme, Ministry of Health, Lilongwe, Malawi
| | | | | | - Peter Troell
- President's Malaria Initiative, Centers for Disease Control and Prevention, Lilongwe, Malawi
| | - Jessica Oyugi
- Division of Parasitic Diseases and Malaria, Centers for Diseases Control and Prevention, Atlanta, GA, USA
| | - Kim Lindblade
- Division of Parasitic Diseases and Malaria, Centers for Diseases Control and Prevention, Atlanta, GA, USA
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Diseases Control and Prevention, Atlanta, GA, USA
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9
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Lynch PA, Boots M. Using evolution to generate sustainable malaria control with spatial repellents. eLife 2016; 5. [PMID: 27776220 PMCID: PMC5089865 DOI: 10.7554/elife.15416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 09/13/2016] [Indexed: 11/24/2022] Open
Abstract
Evolution persistently undermines vector control programs through insecticide resistance. Here we propose a novel strategy which instead exploits evolution to generate and sustain new control tools. Effective spatial repellents are needed to keep vectors out of houses. Our approach generates such new repellents by combining a high-toxicity insecticide with a candidate repellent initially effective against only part of the vector population. By killing mosquitoes that enter treated properties the insecticide selects for vector phenotypes deflected by the repellent, increasing efficacy of the repellent against the target vector population and in turn protecting the insecticide against the spread of insecticide resistance. Using such evolved spatial repellents offers an evolutionarily sustainable, ‘double-dip’ system of disease control combining mortality and repellence. We formalize this idea using models which explore vector population genetics and disease transmission probabilities and show that using evolved spatial repellents is theoretically achievable, effective and sustainable. DOI:http://dx.doi.org/10.7554/eLife.15416.001 Many of the mosquito species that transmit malaria have evolved to bite humans indoors at night, and therefore health programs target them using insecticides sprayed on surfaces inside people’s homes. This strategy, however, stops working when mosquito populations evolve to resist the insecticide used, either because they are immune to its poisonous effects or because they change their behaviour to avoid it. Consequently, there is now a need to develop alternative strategies to control mosquitoes that are more sustainable in the face of evolution. One possibility is repellents that keep mosquitoes out of homes. Lynch and Boots have now asked whether evolution could be used to create effective repellents from substances that initially repel only part of the mosquito population by pairing them with lethal insecticides sprayed inside people’s homes. Mathematical models showed that, before insecticide resistance becomes widespread, this “evolved repellence” approach could reduce the spread of malaria by a similar amount to using insecticides alone. This was particularly true if the models considered that, as well as surviving to give fewer infectious bites, repelled infectious mosquitoes may be less likely to transmit malaria with each feed, for example if they feed more on livestock rather than humans. The models of Lynch and Boots also show that that the success of the evolved repellence concept in a given location depends on a number of factors. The proportion of the starting mosquito population that is repelled or resistant can have a large effect. Similarly, success will also depend on how likely normal, repelled and insecticide-resistant mosquitoes are to reproduce successfully. These values can be influenced by the choice of insecticide and repellent and how the chemicals are applied. Lynch and Boots show that swapping insecticides can allow an evolved repellent to be established where it would otherwise not succeed. Also, the spread of resistance to the paired insecticide is slowed or prevented when the mosquito population evolves to be repelled. Practical laboratory and field- work is now needed to build on this theoretical groundwork and to determine suitable locations and application strategies to exploit this concept as a way to sustainably reduce the spread of malaria in the future. DOI:http://dx.doi.org/10.7554/eLife.15416.002
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Affiliation(s)
- Penelope Anne Lynch
- Department of Biosciences, University of Exeter, Cornwall Campus, Penryn, United Kingdom
| | - Mike Boots
- Department of Biosciences, University of Exeter, Cornwall Campus, Penryn, United Kingdom.,Department of Integrative Biology, University of California, Berkeley, United States
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10
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Samb B, Konate L, Irving H, Riveron JM, Dia I, Faye O, Wondji CS. Investigating molecular basis of lambda-cyhalothrin resistance in an Anopheles funestus population from Senegal. Parasit Vectors 2016; 9:449. [PMID: 27519696 PMCID: PMC4983014 DOI: 10.1186/s13071-016-1735-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/28/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Anopheles funestus is one of the major malaria vectors in tropical Africa, notably in Senegal. The highly anthropophilic and endophilic behaviours of this mosquito make it a good target for vector control operations through the use of insecticide treated nets, long-lasting insecticide nets and indoor residual spraying. However, little is known about patterns of resistance to insecticides and the underlying resistance mechanisms in field populations of this vector in Senegal. METHODS Here, we assessed the susceptibility status of An. funestus populations from Gankette Balla, located in northern Senegal and investigated the potential resistance mechanisms. RESULTS WHO bioassays indicated that An. funestus is resistant to lambda-cyhalothrin 0.05 % (74.64 % mortality), DDT 4 % (83.36 % mortality) and deltamethrin 0.05 % (88.53 % mortality). Suspected resistance was observed to permethrin 0.75 % (91.19 % mortality), bendiocarb 0.1 % (94.13 % mortality) and dieldrin 4 % (96.41 % mortality). However, this population is fully susceptible to malathion 5 % (100 % mortality) and fenitrothion 1 % (100 % mortality). The microarray and qRT-PCR analysis indicated that the lambda-cyhalothrin resistance in Gankette Balla is conferred by metabolic resistance mechanisms under the probable control of cytochrome P450 genes among which CYP6M7 is the most overexpressed. The absence of overexpression of the P450 gene, CYP6P9a, indicates that the resistance mechanism in Senegal is different to that observed in southern Africa. CONCLUSIONS This study represents the first report of pyrethroid and DDT resistance in An. funestus from Senegal and shows that resistance to insecticides is not only confined to An. gambiae as previously thought. Therefore, urgent action should be taken to manage the resistance in this species to ensure the continued effectiveness of malaria control.
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Affiliation(s)
- Badara Samb
- Laboratoire d'Écologie Vectorielle et Parasitaire, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar-Fann, BP, 5005, Sénégal.
| | - Lassana Konate
- Laboratoire d'Écologie Vectorielle et Parasitaire, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar-Fann, BP, 5005, Sénégal
| | - Helen Irving
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jacob M Riveron
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Research Unit Liverpool School of Tropical Medicine, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, P.O Box 288, Yaoundé, Cameroon
| | - Ibrahima Dia
- Unité d'Entomologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP, 220, Dakar, Sénégal
| | - Ousmane Faye
- Laboratoire d'Écologie Vectorielle et Parasitaire, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Dakar-Fann, BP, 5005, Sénégal
| | - Charles S Wondji
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.,Research Unit Liverpool School of Tropical Medicine, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, P.O Box 288, Yaoundé, Cameroon
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Kabula B, Tungu P, Rippon EJ, Steen K, Kisinza W, Magesa S, Mosha F, Donnelly MJ. A significant association between deltamethrin resistance, Plasmodium falciparum infection and the Vgsc-1014S resistance mutation in Anopheles gambiae highlights the epidemiological importance of resistance markers. Malar J 2016; 15:289. [PMID: 27216484 PMCID: PMC4877992 DOI: 10.1186/s12936-016-1331-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/06/2016] [Indexed: 11/16/2022] Open
Abstract
Background The success of malaria vector control is threatened by widespread pyrethroid insecticide resistance. However, the extent to which insecticide resistance impacts transmission is unclear. The objective of this study was to examine the association between the DDT/pyrethroid knockdown resistance mutation Vgsc-1014S, commonly termed kdr, and infection with Plasmodium falciparum sporozoites in Anopheles gambiae. Methods WHO standard methods were used to characterize susceptibility of wild female mosquitoes to 0.05 % deltamethrin. PCR-based molecular diagnostics were used to identify mosquitoes to species and to genotype at the Vgsc-L1014S locus. ELISAs were used to detect the presence of P.falciparum sporozoites and for blood meal identification. Results Anopheles mosquitoes were resistant to deltamethrin with mortality rates of 77.7 % [95 % CI 74.9–80.3 %]. Of 545 mosquitoes genotyped 96.5 % were A. gambiaes.s. and 3.5 % were Anopheles arabiensis. The Vgsc-1014S mutation was detected in both species. Both species were predominantly anthropophagic. In A. gambiaes.s., Vgsc-L1014S genotype was significantly associated with deltamethrin resistance (χ2 = 11.2; p < 0.001). The P. falciparum sporozoite infection rate was 4.2 %. There was a significant association between the presence of sporozoites and Vgsc-L1014S genotype in A. gambiaes.s. (χ2 = 4.94; p = 0.026). Conclusions One marker, Vgsc-1014S, was associated with insecticide resistance and P. falciparum infection in wild-caught mixed aged populations of A. gambiaes.s. thereby showing how resistance may directly impact transmission.
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Affiliation(s)
- Bilali Kabula
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania.,Amani Research Centre, National Institute for Medical Research, Muheza, Tanzania.,Tukuyu Research Centre, National Institute for Medical Research, Tukuyu, Tanzania
| | - Patrick Tungu
- Amani Research Centre, National Institute for Medical Research, Muheza, Tanzania
| | - Emily J Rippon
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Keith Steen
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - William Kisinza
- Amani Research Centre, National Institute for Medical Research, Muheza, Tanzania
| | - Stephen Magesa
- Amani Research Centre, National Institute for Medical Research, Muheza, Tanzania.,Global Health Division, RTI International, Dar es Salaam, Tanzania
| | - Franklin Mosha
- Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania
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12
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Retraction: Resistance to DDT and Pyrethroids and Increased kdr Mutation Frequency in An. gambiae after the Implementation of Permethrin-Treated Nets in Senegal. PLoS One 2016; 11:e0156195. [PMID: 27196334 PMCID: PMC4873149 DOI: 10.1371/journal.pone.0156195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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13
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Sangba MLO, Deketramete T, Wango SP, Kazanji M, Akogbeto M, Ndiath MO. Insecticide resistance status of the Anopheles funestus population in Central African Republic: a challenge in the war. Parasit Vectors 2016; 9:230. [PMID: 27113956 PMCID: PMC4845364 DOI: 10.1186/s13071-016-1510-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/14/2016] [Indexed: 11/18/2022] Open
Abstract
Background In the Central African Republic, malaria is a major public health problem and the leading cause of death among children. This disease appears to be hyperendemic but no substantial entomological data, including data on Anopheles spp. susceptibility to insecticides, is available. This study evaluates, for the first time in the CAR, the status of insecticide resistance in the Anopheles funestus population, the second major vector of malaria in Africa. Methods WHO standard bioassay susceptibility tests were performed on the An. funestus population using F1 generation from gravid females mosquitoes (F0) collected by manual aspirator sampling of households in Gbanikola, Bangui in October 2014 to assess: (i) An. funestus susceptibility to bendiocarb, malathion, permethrin, lamda-cyhalothrin, deltamethrin and DDT, and (ii) the effect of pre-exposure to the piperonyl butoxide (PBO) synergist on insecticide susceptibility. Additional tests were conducted to investigate metabolic resistance status (cytochrome P450 monooxygenases, glutathione S-transferases, and esterases). Results A high phenotypic resistance of An. funestus population to malathion, DDT and pyrethroids was observed with a mortality rate ranging from 23 to 74 %. For the pyrethroid groups, the mortality rate was 35, 31 and 23 % for lambda-cyhalothrin, deltamethrin, and permethrin, respectively. In contrast a 100 % mortality rate to bendiocarb was recorded. Knockdown time (KDT) was long for all pyrethroids, DDT and malathion with KDT50 higher than 50 min. Pre-exposure of An. funestus to PBO synergist significantly restored susceptibility to all pyrethroids (Fisher's exact test P <0.0001) but not in DDT (Fisher's exact test P = 0.724). Data from biochemical tests suggest the involvement of cytochrome P450 monooxygenases, esterases and glutatione S-transferases in the resistance of An. funestus population from Gbanikola (Wilcoxon test P <0.05). Conclusion Evidence of biochemical resistance to insecticide was detected in An. funestus population from the district of Gbanikola, Bangui. This study suggests that detoxifying enzymes are involved in insecticide resistance of An. funestus. However, despite disruptive violence, further research is urgently needed to assess the insecticide susceptibility status of An. funestus population in all CAR regions; insecticide resistance could rapidly compromise the success of malaria control programs.
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Affiliation(s)
- Marina Lidwine Olé Sangba
- G4 Malaria Group Institut Pasteur in Bangui, Bangui, Central African Republic.,Faculté des Sciences et Techniques, Université d'Abomey Calavi, Cotonou, Bénin
| | - Tanguy Deketramete
- G4 Malaria Group Institut Pasteur in Bangui, Bangui, Central African Republic.,Faculté des Sciences et Techniques, Laboratoire de Biologie Animale Appliquée et de Biodiversité, Université de Bangui, Bangui, Central African Republic
| | - Solange Patricia Wango
- Faculté des Sciences et Techniques, Laboratoire de Biologie Animale Appliquée et de Biodiversité, Université de Bangui, Bangui, Central African Republic
| | - Mirdad Kazanji
- Virology Department, Institut Pasteur in Bangui, Bangui, Central African Republic
| | - Martin Akogbeto
- Faculté des Sciences et Techniques, Université d'Abomey Calavi, Cotonou, Bénin.,Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, 06 BP 2604, Bénin
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14
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Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam, India. PLoS One 2016; 11:e0151786. [PMID: 27010649 PMCID: PMC4807056 DOI: 10.1371/journal.pone.0151786] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/03/2016] [Indexed: 11/19/2022] Open
Abstract
During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC) and Balipara primary health centre (BPHC) areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT50 and KDT99 values for DDT. Probit model used to calculate the KDT50 and KDT99 values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (p<0.05) and An. vagus in BPHC (χ2 = 25.3; p = 0.0), and also for deltamethrin to An. vagus in BPHC area (χ2 = 15.4; p = 0.004). Minimum infection rate (MIR) of Plasmodium sporozoite for An. vagus was 0.56 in OPHC and 0.13 in BPHC, while for An. annularis MIR was found to be 0.22 in OPHC. Resistance management strategies should be identified to delay the expansion of resistance. Testing of field caught Anopheles vectors from different endemic areas for the presence of malaria sporozoite may be useful to ensure their role in malaria transmission.
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15
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Owusu EDA, Buabeng V, Dadzie S, Brown CA, Grobusch MP, Mens P. Characteristics of asymptomatic Plasmodium spp. parasitaemia in Kwahu-Mpraeso, a malaria endemic mountainous district in Ghana, West Africa. Malar J 2016; 15:38. [PMID: 26801407 PMCID: PMC4724116 DOI: 10.1186/s12936-015-1066-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 12/22/2015] [Indexed: 12/01/2022] Open
Abstract
Background Malaria control efforts in Ghana have reduced the countrywide average malaria prevalence from 71 % in 2000 to about 51 % in 2012; however, its main focus is on symptomatic malaria. If further progress is to be made, parasite
reservoirs in asymptomatic carriers need to be moved into focus. This study profiles asymptomatic Plasmodium spp. parasitaemia amongst residents of mountainous Kwahu-Mpraeso in the Eastern region of Ghana. Methods A cross-sectional study of 360 residents was carried out from October to December 2013. This included recording demographics, malaria testing of asymptomatic residents, and gathering of their malaria history. Assessment of malaria transmission was done with molecular identification of vectors, determination of sporozoite rate, insecticide resistance status and biting pattern. Univariate and multivariate analysis were used to establish risk determinants. Results In Mpraeso, in the Kwahu highland of Eastern Region, children were at higher risk of asymptomatic parasitaemia, thereby contributing to the parasite reservoir and hence sustained malaria transmission. As well, findings suggested Hb AC genotype influenced susceptibility to asymptomatic malaria with 8.03-fold increase in odds (univariate) and 11.92-fold higher odds (multivariate) than the normal Hb AA. The mosquito vector predominant in the area was Anopheles gambiae sensu stricto of the homozygous pyrethroid resistant form (RR); with biting mainly occurring indoors. Conclusion For an effective malaria control in this area, interventions should be formulated and implemented to target asymptomatic parasite reservoirs; especially in children and people with Hb AC. The dominant vector species An. gambiae s.s. and its feeding patterns of biting indoors should also be considered.
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Affiliation(s)
- Ewurama D A Owusu
- Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Centre, Centre of Tropical Medicine and Travel Medicine, University of Amsterdam, Amsterdam, The Netherlands. .,Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana, Accra, Ghana. .,Department of Parasitology, KIT Biomedical Research Institute, Amsterdam, The Netherlands.
| | - Vincent Buabeng
- Medical Laboratory Department, Atibie Government Hospital, Kwahu-Atibie, Ghana.
| | - Samuel Dadzie
- Medical Entomology Unit, Department of Parasitology, Noguchi Memorial Institute of Medical Research, University of Ghana, Accra, Ghana.
| | - Charles A Brown
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, College of Health Sciences, University of Ghana, Accra, Ghana.
| | - Martin P Grobusch
- Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Centre, Centre of Tropical Medicine and Travel Medicine, University of Amsterdam, Amsterdam, The Netherlands. .,Centre de Recherches Médicales de Lambaréné (CERMEL), Hôpital Albert Schweitzer, Lambaréné, Gabon. .,Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
| | - Petra Mens
- Department of Infectious Diseases, Division of Internal Medicine, Academic Medical Centre, Centre of Tropical Medicine and Travel Medicine, University of Amsterdam, Amsterdam, The Netherlands. .,Department of Parasitology, KIT Biomedical Research Institute, Amsterdam, The Netherlands.
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16
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Mitri C, Markianos K, Guelbeogo WM, Bischoff E, Gneme A, Eiglmeier K, Holm I, Sagnon N, Vernick KD, Riehle MM. The kdr-bearing haplotype and susceptibility to Plasmodium falciparum in Anopheles gambiae: genetic correlation and functional testing. Malar J 2015; 14:391. [PMID: 26445487 PMCID: PMC4596459 DOI: 10.1186/s12936-015-0924-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/29/2015] [Indexed: 11/25/2022] Open
Abstract
Background Members of the Anophelesgambiae species complex are primary vectors of human malaria in Africa. It is known that a large haplotype shared between An. gambiae and Anophelescoluzzii by introgression carries point mutations of the voltage-gated sodium channel gene para, including the L1014F kdr mutation associated with insensitivity to pyrethroid insecticides. Carriage of L1014F kdr is also correlated with higher susceptibility to infection with Plasmodium falciparum. However, the genetic mechanism and causative gene(s) underlying the parasite susceptibility phenotype are not known. Methods Mosquitoes from the wild Burkina Faso population were challenged by feeding on natural P. falciparum gametocytes. Oocyst infection phenotypes were determined and were tested for association with SNP genotypes. Candidate genes in the detected locus were prioritized and RNAi-mediated gene silencing was used to functionally test for gene effects on P. falciparum susceptibility. Results A genetic locus, Pfin6, was identified that influences infection levels of P. falciparum in mosquitoes. The locus segregates as a ~3 Mb haplotype carrying 65 predicted genes including the para gene. The haplotype carrying the kdr allele of para is linked to increased parasite infection prevalence, but many single nucleotide polymorphisms on the haplotype are also equally linked to the infection phenotype. Candidate genes in the haplotype were prioritized and functionally tested. Silencing of para did not influence P. falciparum infection, while silencing of a predicted immune gene, serine protease ClipC9, allowed development of significantly increased parasite numbers. Conclusions Genetic variation influencing Plasmodium infection in wild Anopheles is linked to a natural ~3 megabase haplotype on chromosome 2L that carries the kdr allele of the para gene. Evidence suggests that para gene function does not directly influence parasite susceptibility, and the association of kdr with infection may be due to tight linkage of kdr with other gene(s) on the haplotype. Further work will be required to determine if ClipC9 influences the outcome of P. falciparum infection in nature, as well as to confirm the absence of a direct influence by para. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0924-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christian Mitri
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, CNRS Unit of Hosts, Vectors and Pathogens (URA3012), Lab GGIV, Institut Pasteur, 28 rue du Dr Roux, 75015, Paris, France.
| | - Kyriacos Markianos
- Program in Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Wamdaogo M Guelbeogo
- Centre National de Recherche et de Formation sur le Paludisme, 01 BP 2208, Ouagadougou, Burkina Faso.
| | - Emmanuel Bischoff
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, CNRS Unit of Hosts, Vectors and Pathogens (URA3012), Lab GGIV, Institut Pasteur, 28 rue du Dr Roux, 75015, Paris, France.
| | - Awa Gneme
- Centre National de Recherche et de Formation sur le Paludisme, 01 BP 2208, Ouagadougou, Burkina Faso.
| | - Karin Eiglmeier
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, CNRS Unit of Hosts, Vectors and Pathogens (URA3012), Lab GGIV, Institut Pasteur, 28 rue du Dr Roux, 75015, Paris, France.
| | - Inge Holm
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, CNRS Unit of Hosts, Vectors and Pathogens (URA3012), Lab GGIV, Institut Pasteur, 28 rue du Dr Roux, 75015, Paris, France.
| | - N'Fale Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, 01 BP 2208, Ouagadougou, Burkina Faso.
| | - Kenneth D Vernick
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, CNRS Unit of Hosts, Vectors and Pathogens (URA3012), Lab GGIV, Institut Pasteur, 28 rue du Dr Roux, 75015, Paris, France. .,Department of Microbiology, University of Minnesota, Saint Paul, MN, 55108, USA.
| | - Michelle M Riehle
- Department of Microbiology, University of Minnesota, Saint Paul, MN, 55108, USA.
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Emerging knock-down resistance in Anopheles arabiensis populations of Dakar, Senegal: first evidence of a high prevalence of kdr-e mutation in West African urban area. Malar J 2015; 14:364. [PMID: 26395241 PMCID: PMC4579585 DOI: 10.1186/s12936-015-0898-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 09/14/2015] [Indexed: 11/30/2022] Open
Abstract
Background Urban malaria is now considered a major emerging health problem in Africa and urban insecticide resistance may represent a serious threat to the ambitious programme of further scaling-up coverage with long-lasting insecticide-treated bed nets and indoor residual spray. This study evaluates the levels and mechanisms of insecticide resistance in Anopheles gambiae populations in 44 urban areas of Dakar in a longitudinal entomological surveillance study. Methods Adult mosquitoes sampled by night-landing catches at 44 sites across Dakar from 2007 to 2010 were genotyped to assess the frequency and distribution of resistance alleles. In addition World Health Organization susceptibility tests to six insecticides were performed on F0 adults issuing from immature stages of An. gambiae s.l. sampled in August 2010, 2011 and 2012 in three sites of Dakar: Pikine, Thiaroye and Almadies and repeated in 2012 with three of the insecticides after PBO exposure to test for mechanisms of oxydase resistance. Species, molecular forms and the presence of kdr and ace-1 mutations were assessed by polymerase chain reaction. Results High frequencies of the kdr-e allele, ranging from 35 to 100 %, were found in Anopheles arabiensis at all 44 sites. The insecticide susceptibility tests indicated sensitivity to bendiocarb in Almadies in 2010 and 2011 and in Yarakh between 2010 and 2012 and sensitivity to fenitrothion in Almadies in 2010. The mortality rate of EE genotype mosquitoes was lower and that of SS mosquitoes was higher than that of SE mosquitoes, while the mortality rate of the SW genotype was slightly higher than that of the SE genotype. Pyperonyl butoxide (PBO) had a significant effect on mortality in Pikine (OR = 1.4, 95 % CI = 1.3–1.5, with mortality of 42–55 % after exposure and 11–17 % without PBO) and Yarakh (OR = 1.6, 95 % CI = 1.4–1.7, with mortality of 68–81 % after exposure and 23–37 % without), but not in Almadies (OR = 1.0, 95 % CI = 0.9–1.1). Conclusion A high prevalence of kdr-e in West Africa was demonstrated, and knock-down resistance mechanisms predominate although some oxidases mechanisms (cytochrome P450 monooxygenases) also occur. In view of the increased use of insecticides and the proposed role of the kdr gene in the susceptibility of Anopheles to Plasmodium, this finding will significantly affect the success of vector control programmes. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0898-6) contains supplementary material, which is available to authorized users.
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18
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Cisse MBM, Keita C, Dicko A, Dengela D, Coleman J, Lucas B, Mihigo J, Sadou A, Belemvire A, George K, Fornadel C, Beach R. Characterizing the insecticide resistance of Anopheles gambiae in Mali. Malar J 2015; 14:327. [PMID: 26296644 PMCID: PMC4546276 DOI: 10.1186/s12936-015-0847-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 08/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impact of indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs), key components of the national malaria control strategy of Mali, is threatened by vector insecticide resistance. The objective of this study was to assess the level of insecticide resistance in Anopheles gambiae sensu lato populations from Mali against four classes of insecticide recommended for IRS: organochlorines (OCs), pyrethroids (PYs), carbamates (CAs) and organophosphates (OPs). Characterization of resistance was done in 13 sites across southern Mali and assessed presence and distribution of physiological mechanisms that included target-site modifications: knockdown resistance (kdr) and altered acetycholinesterase (AChE), and/or metabolic mechanisms: elevated esterases, glutathione S-transferases (GSTs), and monooxygenases. METHODS The World Health Organization (WHO) tube test was used to determine phenotypic resistance of An. gambiae s.l. to: dichlorodiphenyltrichloroethane (DDT) (OC), deltamethrin (PY), lambda-cyhalothrin (PY), bendiocarb (CA), and fenitrothion (OP). Identification of sibling species and presence of the ace-1 (R) and Leu-Phe kdr, resistance-associated mutations, were determined using polymerase chain reaction (PCR) technology. Biochemical assays were conducted to detect increased activity of GSTs, oxidases and esterases. RESULTS Populations tested showed high levels of resistance to DDT in all 13 sites, as well as increased resistance to deltamethrin and lambda-cyhalothrin in 12 out of 13 sites. Resistance to fenitrothion and bendiocarb was detected in 1 and 4 out of 13 sites, respectively. Anopheles coluzzii, An. gambiae sensu stricto and Anopheles arabiensis were identified with high allelic frequencies of kdr in all sites where each of the species were found (13, 12 and 10 sites, respectively). Relatively low allelic frequencies of ace-1 (R) were detected in four sites where this assessment was conducted. Evidence of elevated insecticide metabolism, based on oxidase, GSTs and esterase detoxification, was also documented. CONCLUSION Multiple insecticide-resistance mechanisms have evolved in An. coluzzii, An. gambiae s.s. and An. arabiensis in Mali. These include at least two target site modifications: kdr, and ace-1 (R) , as well as elevated metabolic detoxification systems (monooxygenases and esterases). The selection pressure for resistance could have risen from the use of these insecticides in agriculture, as well as in public health. Resistance management strategies, based on routine resistance monitoring to inform insecticide-based malaria vector control in Mali, are recommended.
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Affiliation(s)
- Moussa B M Cisse
- PMI Africa Indoor Residual Spraying Project, Abt Associates, Mali, Cite du Niger. BP: 34, Bamako, Mali.
| | - Chitan Keita
- PMI Africa Indoor Residual Spraying Project, Abt Associates, Mali, Cite du Niger. BP: 34, Bamako, Mali.
| | - Abdourhamane Dicko
- National Malaria Control Programme, Badalabougou, Rue 108 Porte 106, Bamako, Mali.
| | - Dereje Dengela
- PMI Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave, Suite 800 North, Bethesda, MD, 20814, USA.
| | - Jane Coleman
- PMI Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave, Suite 800 North, Bethesda, MD, 20814, USA.
| | - Bradford Lucas
- PMI Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave, Suite 800 North, Bethesda, MD, 20814, USA.
| | - Jules Mihigo
- President's Malaria Initiative USAID, ACI2000, Rue 243, Porte 297-BP 34, Bamako, Mali.
| | - Aboubacar Sadou
- President's Malaria Initiative USAID, ACI2000, Rue 243, Porte 297-BP 34, Bamako, Mali.
| | - Allison Belemvire
- President's Malaria Initiative USAID, 1300 Pennsylvania Avenue NW, Washington DC, USA.
| | - Kristen George
- President's Malaria Initiative USAID, 1300 Pennsylvania Avenue NW, Washington DC, USA.
| | - Christen Fornadel
- President's Malaria Initiative USAID, 1300 Pennsylvania Avenue NW, Washington DC, USA.
| | - Raymond Beach
- Division of Parasitic Diseases and Malaria, Center for Global Health, US Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA.
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Quiñones ML, Norris DE, Conn JE, Moreno M, Burkot TR, Bugoro H, Keven JB, Cooper R, Yan G, Rosas A, Palomino M, Donnelly MJ, Mawejje HD, Eapen A, Montgomery J, Coulibaly MB, Beier JC, Kumar A. Insecticide Resistance in Areas Under Investigation by the International Centers of Excellence for Malaria Research: A Challenge for Malaria Control and Elimination. Am J Trop Med Hyg 2015; 93:69-78. [PMID: 26259947 PMCID: PMC4574276 DOI: 10.4269/ajtmh.14-0844] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/30/2015] [Indexed: 12/16/2022] Open
Abstract
Scale-up of the main vector control interventions, residual insecticides sprayed on walls or structures and/or impregnated in bed nets, together with prompt diagnosis and effective treatment, have led to a global reduction in malaria transmission. However, resistance in vectors to almost all classes of insecticides, particularly to the synthetic pyrethroids, is posing a challenge to the recent trend of declining malaria. Ten International Centers of Excellence for Malaria Research (ICEMR) located in the most malaria-endemic regions of the world are currently addressing insecticide resistance in the main vector populations, which not only threaten hope for elimination in malaria-endemic countries but also may lead to reversal where notable reductions in malaria have been documented. This communication illustrates the current status of insecticide resistance with a focus on the countries where activities are ongoing for 9 out of the 10 ICEMRs. Most of the primary malaria vectors in the ICEMR countries exhibit insecticide resistance, albeit of varying magnitude, and spanning all mechanisms of resistance. New alternatives to the insecticides currently available are still to be fully developed for deployment. Integrated vector management principles need to be better understood and encouraged, and viable insecticide resistance management strategies need to be developed and implemented.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ashwani Kumar
- *Address correspondence to Ashwani Kumar, National Institute of Malaria Research (ICMR), Department of Health Research (DHR), Government of India, Field Station, DHS Building, Campal, Panaji 403 001, Goa, India. E-mail:
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20
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Gnanguenon V, Agossa FR, Badirou K, Govoetchan R, Anagonou R, Oke-Agbo F, Azondekon R, AgbanrinYoussouf R, Attolou R, Tokponnon FT, Aïkpon R, Ossè R, Akogbeto MC. Malaria vectors resistance to insecticides in Benin: current trends and mechanisms involved. Parasit Vectors 2015; 8:223. [PMID: 25886599 PMCID: PMC4395909 DOI: 10.1186/s13071-015-0833-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/29/2015] [Indexed: 11/29/2022] Open
Abstract
Background Insecticides are widely used to control malaria vectors and have significantly contributed to the reduction of malaria-caused mortality. In addition, the same classes of insecticides were widely introduced and used in agriculture in Benin since 1980s. These factors probably contributed to the selection of insecticide resistance in malaria vector populations reported in several localities in Benin. This insecticide resistance represents a threat to vector control tool and should be monitored. The present study reveals observed insecticide resistance trends in Benin to help for a better management of insecticide resistance. Methods Mosquito larvae were collected in eight sites and reared in laboratory. Bioassays were conducted on the adult mosquitoes upon the four types of insecticide currently used in public health in Benin. Knock-down resistance, insensitive acetylcholinesterase-1 resistance, and metabolic resistance analysis were performed in the mosquito populations based on molecular and biochemical analysis. The data were mapped using Geographical Information Systems (GIS) with Arcgis software. Results Mortalities observed with Deltamethrin (pyrethroid class) were less than 90% in 5 locations, between 90-97% in 2 locations, and over 98% in one location. Bendiocarb (carbamate class) showed mortalities ranged 90-97% in 2 locations and were over 98% in the others locations. A complete susceptibility to Pirimiphos methyl and Fenitrothion (organophosphate class) was observed in all locations with 98-100% mortalities. Knock-down resistance frequencies were high (0.78-0.96) and similar between Anopheles coluzzii, Anopheles gambiae, Anopheles arabiensis, and Anopheles melas. Insensitive acetylcholinesterase-1 was rare (0.002-0.1) and only detected in Anopheles gambiae in concomitance with Knock-down resistance mutation. The maps showed a large distribution of Deltamethrin resistance, Knock-down mutation and metabolic resistance throughout the country, a suspected resistance to Bendiocarb and detection of insensitive acetylcholinesterase-1 from northern Benin, and a wide distribution of susceptible vectors to Pirimiphos methyl and Fenitrothion. Conclusion This study showed a widespread resistance of malaria vectors to pyrethroid previously located in southern Benin, an early emergence of carbamates resistance from northern Benin and a full susceptibility to organophosphates. Several resistance mechanisms were detected in vectors with a potential cross resistance to pyrethroids through Knock-down and metabolic resistance mechanisms.
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Affiliation(s)
- Virgile Gnanguenon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Fiacre R Agossa
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Kefilath Badirou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Renaud Govoetchan
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Rodrigue Anagonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Fredéric Oke-Agbo
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.
| | - Roseric Azondekon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin.
| | - Ramziath AgbanrinYoussouf
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Roseline Attolou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | | | - Rock Aïkpon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
| | - Razaki Ossè
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Université d'Agriculture de Kétou, Kétou, Benin.
| | - Martin C Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin. .,Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Benin.
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Okorie PN, Ademowo GO, Irving H, Kelly-Hope LA, Wondji CS. Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan, Southwest Nigeria. MEDICAL AND VETERINARY ENTOMOLOGY 2015; 29:44-50. [PMID: 25417803 PMCID: PMC4319996 DOI: 10.1111/mve.12089] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 08/26/2014] [Accepted: 09/03/2014] [Indexed: 06/04/2023]
Abstract
The emergence of insecticide resistance in Anopheles (Diptera: Culicidae) mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and the frequency of knock-down resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and Anopheles gambiae Giles from the Ojoo and Bodija areas of Ibadan, in southwest Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and organochlorines was assessed using World Health Organization (WHO) bioassays. A subset of the mosquitoes exposed to pyrethroids and DDT was used for species and molecular form identification; kdr genotyping was determined using the TaqMan real-time polymerase chain reaction assay. The mosquitoes were resistant to pyrethroids and DDT but completely susceptible to organophosphates and carbamates. Bodija samples (n = 186) consisted of An. gambiae (91.4%) and An. coluzzii (8.1%) and included one An. coluzzii/An. gambiae hybrid specimen. All mosquitoes screened in Ojoo (n = 26) were An. gambiae. The 1014F kdr mutation was detected at frequencies of 24.5 and 5.8% in Bodija and Ojoo, respectively. No correlation was observed between kdr genotypes and resistance phenotypes. The results indicate that metabolic resistance probably plays an important role in the development of resistance and highlight the need to implement insecticide resistance management strategies.
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Affiliation(s)
- Patricia N. Okorie
- Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - George O. Ademowo
- Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Helen Irving
- Centre for Neglected Tropical Diseases and Vector Group – Liverpool School of Tropical Medicine, Liverpool, UK
| | - Louise A. Kelly-Hope
- Centre for Neglected Tropical Diseases and Vector Group – Liverpool School of Tropical Medicine, Liverpool, UK
| | - Charles S. Wondji
- Centre for Neglected Tropical Diseases and Vector Group – Liverpool School of Tropical Medicine, Liverpool, UK
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22
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Lindblade KA, Mwandama D, Mzilahowa T, Steinhardt L, Gimnig J, Shah M, Bauleni A, Wong J, Wiegand R, Howell P, Zoya J, Chiphwanya J, Mathanga DP. A cohort study of the effectiveness of insecticide-treated bed nets to prevent malaria in an area of moderate pyrethroid resistance, Malawi. Malar J 2015; 14:31. [PMID: 25627987 PMCID: PMC4318190 DOI: 10.1186/s12936-015-0554-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 01/07/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Insecticide-treated bed nets (ITNs) are the cornerstone of malaria control in sub-Saharan Africa but their effectiveness may be compromised by the spread of pyrethroid resistance among malaria vectors. The objective of this investigation was to assess the effectiveness of ITNs to prevent malaria in an area of Malawi with moderate pyrethroid resistance. METHODS One deltamethrin ITN was distributed in the study area for every two individuals in each household plus one extra ITN for households with an odd number of residents. A fixed cohort of 1,199 children aged six to 59 months was seen monthly for one year and at sick visits to measure malaria infection and use of ITNs. Insecticide resistance among malaria vectors was measured. The effect of ITN use on malaria incidence was assessed, adjusting for potential confounders using generalized estimating equations accounting for repeated measures. RESULTS There were 1,909 infections with Plasmodium falciparum over 905 person-years at risk (PYAR), resulting in an observed incidence of 2.1 infections per person-year (iPPY). ITNs were used during 97% of the PYAR. The main vector was Anopheles funestus: mortality in WHO tube assays after exposure to 0.05% deltamethrin was 38% (95% confidence interval (CI) 29-47), and resistance was due to elevated oxidase enzymes. After adjusting for potential confounders, the incidence of malaria infection among ITN users was 1.7 iPPY (95% CI 1.5-2.1) and among non-bed net users was 2.6 iPPY (95% CI 2.0-3.3). Use of ITNs reduced the incidence of malaria infection by 30% (rate ratio 0.7; 95% CI, 0.5-0.8) compared to no bed nets. CONCLUSION ITNs significantly reduced the incidence of malaria infection in children in an area with moderate levels of pyrethroid resistance and considerable malaria transmission. This is the first study to show that ITNs provide protection in areas where pyrethroid-resistant An. funestus is the major malaria vector. Malaria control programmes should continue to distribute and promote ITNs in areas with low to moderate pyrethroid resistance; however, insecticide resistance may intensify further and it is not known whether ITNs will remain effective at higher levels of resistance. There is an urgent need to identify or develop new insecticides and technologies to limit the vulnerability of ITNs to insecticide resistance.
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Affiliation(s)
- Kim A Lindblade
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Dyson Mwandama
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Themba Mzilahowa
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Laura Steinhardt
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - John Gimnig
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Monica Shah
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Andy Bauleni
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
| | - Jacklyn Wong
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Ryan Wiegand
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - Paul Howell
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, 1600 Clifton Rd. NE MS A-06, Atlanta, GA, 30333, USA.
| | - John Zoya
- National Malaria Control Programme, Ministry of Public Health, Lilongwe, Malawi.
| | - John Chiphwanya
- National Malaria Control Programme, Ministry of Public Health, Lilongwe, Malawi.
| | - Don P Mathanga
- Malaria Alert Centre, Malawi College of Medicine, Blantyre, Malawi.
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Silva APB, Santos JMM, Martins AJ. Mutations in the voltage-gated sodium channel gene of anophelines and their association with resistance to pyrethroids - a review. Parasit Vectors 2014; 7:450. [PMID: 25292318 PMCID: PMC4283120 DOI: 10.1186/1756-3305-7-450] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/01/2014] [Indexed: 12/14/2022] Open
Abstract
Constant and extensive use of chemical insecticides has created a selection pressure and favored resistance development in many insect species worldwide. One of the most important pyrethroid resistance mechanisms is classified as target site insensitivity, due to conformational changes in the target site that impair a proper binding of the insecticide molecule. The voltage-gated sodium channel (NaV) is the target of pyrethroids and DDT insecticides, used to control insects of medical, agricultural and veterinary importance, such as anophelines. It has been reported that the presence of a few non-silent point mutations in the NaV gene are associated with pyrethroid resistance, termed as 'kdr' (knockdown resistance) for preventing the knockdown effect of these insecticides. The presence of these mutations, as well as their effects, has been thoroughly studied in Anopheles mosquitoes. So far, kdr mutations have already been detected in at least 13 species (Anopheles gambiae, Anopheles arabiensis, Anopheles sinensis, Anopheles stephensi, Anopheles subpictus, Anopheles sacharovi, Anopheles culicifacies, Anopheles sundaicus, Anopheles aconitus, Anopheles vagus, Anopheles paraliae, Anopheles peditaeniatus and Anopheles albimanus) from populations of African, Asian and, more recently, American continents. Seven mutational variants (L1014F, L1014S, L1014C, L1014W, N1013S, N1575Y and V1010L) were described, with the highest prevalence of L1014F, which occurs at the 1014 site in NaV IIS6 domain. The increase of frequency and distribution of kdr mutations clearly shows the importance of this mechanism in the process of pyrethroid resistance. In this sense, several species-specific and highly sensitive methods have been designed in order to genotype individual mosquitoes for kdr in large scale, which may serve as important tolls for monitoring the dynamics of pyrethroid resistance in natural populations. We also briefly discuss investigations concerning the course of Plasmodium infection in kdr individuals. Considering the limitation of insecticides available for employment in public health campaigns and the absence of a vaccine able to brake the life cycle of the malaria parasites, the use of pyrethroids is likely to remain as the main strategy against mosquitoes by either indoor residual spraying (IR) and insecticide treated nets (ITN). Therefore, monitoring insecticide resistance programs is a crucial need in malaria endemic countries.
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Affiliation(s)
- Ana Paula B Silva
- />Laboratório de Malária e Dengue, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Petrópolis, CEP 69067-375 Manaus, Amazonas Brazil
| | - Joselita Maria M Santos
- />Laboratório de Malária e Dengue, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Petrópolis, CEP 69067-375 Manaus, Amazonas Brazil
| | - Ademir J Martins
- />Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- />Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
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Kabula B, Tungu P, Malima R, Rowland M, Minja J, Wililo R, Ramsan M, McElroy PD, Kafuko J, Kulkarni M, Protopopoff N, Magesa S, Mosha F, Kisinza W. Distribution and spread of pyrethroid and DDT resistance among the Anopheles gambiae complex in Tanzania. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:244-52. [PMID: 24192019 PMCID: PMC10884793 DOI: 10.1111/mve.12036] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/10/2013] [Accepted: 09/19/2013] [Indexed: 06/02/2023]
Abstract
The development of insecticide resistance is a threat to the control of malaria in Africa. We report the findings of a national survey carried out in Tanzania in 2011 to monitor the susceptibility of malaria vectors to pyrethroid, organophosphate, carbamate and DDT insecticides, and compare these findings with those identified in 2004 and 2010. Standard World Health Organization (WHO) methods were used to detect knock-down and mortality rates in wild female Anopheles gambiae s.l. (Diptera: Culicidae) collected from 14 sentinel districts. Diagnostic doses of the pyrethroids deltamethrin, lambdacyhalothrin and permethrin, the carbamate propoxur, the organophosphate fenitrothion and the organochlorine DDT were used. Anopheles gambiae s.l. was resistant to permethrin in Muleba, where a mortality rate of 11% [95% confidence interval (CI) 6-19%] was recorded, Muheza (mortality rate of 75%, 95% CI 66-83%), Moshi and Arumeru (mortality rates of 74% in both). Similarly, resistance was reported to lambdacyhalothrin in Muleba, Muheza, Moshi and Arumeru (mortality rates of 31-82%), and to deltamethrin in Muleba, Moshi and Muheza (mortality rates of 28-75%). Resistance to DDT was reported in Muleba. No resistance to the carbamate propoxur or the organophosphate fenitrothion was observed. Anopheles gambiae s.l. is becoming resistant to pyrethoids and DDT in several parts of Tanzania. This has coincided with the scaling up of vector control measures. Resistance may impair the effectiveness of these interventions and therefore demands close monitoring and the adoption of a resistance management strategy.
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Affiliation(s)
- B Kabula
- Amani Research Centre, National Institute for Medical Research, Ubwari, Muheza, Tanzania; Department of Parasitology and Entomology, Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
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Ndiath MO, Cailleau A, Diedhiou SM, Gaye A, Boudin C, Richard V, Trape JF. Effects of the kdr resistance mutation on the susceptibility of wild Anopheles gambiae populations to Plasmodium falciparum: a hindrance for vector control. Malar J 2014; 13:340. [PMID: 25176292 PMCID: PMC4159551 DOI: 10.1186/1475-2875-13-340] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 08/26/2014] [Indexed: 01/10/2023] Open
Abstract
Background In the context of generalization of insecticide resistance, the hypothesis that insecticide resistance has a positive impact on the capacity of mosquitoes to transmit malaria constitutes a hindrance for malaria elimination. The aim of this study was to investigated populations of Anopheles coluzzii and Anopheles gambiae S molecular form to assess whether different genotypes at the kdr locus are responsible for different susceptibility to Plasmodium falciparum infection. Methods F3 progeny of An. gambiae s.l. collected in Dielmo were infected by direct membrane feeding with P. falciparum gametocyte-containing blood sampled from volunteer patients. The presence of oocysts was determined by light microscopy after seven days, and the presence of sporozoites by ELISA after 14 days. Mosquito species and molecular forms were identified by PCR. Generalized linear models were performed using the R software to test the effect of explanatory variables including the genotype at the kdr locus on infection rate and density. Results The odds of being infected with oocysts and sporozoites were greater in RS and RR groups than in SS groups (χ2 = 42.8, df = 1, P(>χ2) = 6.1e-11). The density of infection was also dependent on genotype, with RR and RS genotypes showing denser infection than SS genotypes. Pairwise comparisons of oocyst number and absorbance indicated sometime a small betwen species (i.e. between An. gambiae S form, and An. coluzzii), but the effect of genotype was much more important. Conclusion The presence of the resistance allele at the kdr locus increases susceptibility to Plasmodium not only at the oocyst stage but also at the sporozoite stage in non-genetically modified wild mosquitoes. These results have significant implications and should be taken into account in the development of strategies for malaria control.
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Affiliation(s)
- Mamadou Ousmane Ndiath
- G4 Group, Institut Pasteur International Network, Institut Pasteur de Bangui, Bangui BP 923, Central African Republic.
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Foster SR, Galanzha EI, Totten DC, Beneš H, Shmookler Reis RJ, Zharov VP. Photoacoustically-guided photothermal killing of mosquitoes targeted by nanoparticles. JOURNAL OF BIOPHOTONICS 2014; 7:465-473. [PMID: 23450780 DOI: 10.1002/jbio.201200199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/04/2013] [Accepted: 01/18/2013] [Indexed: 06/01/2023]
Abstract
In biomedical applications, nanoparticles have demonstrated the potential to eradicate abnormal cells in small localized pathological zones associated with cancer or infections. Here, we introduce a method for nanotechnology-based photothermal (PT) killing of whole organisms considered harmful to humans or the environment. We demonstrate that laser-induced thermal, and accompanying nano- and microbubble phenomena, can injure or kill C. elegans and mosquitoes fed carbon nanotubes, gold nanospheres, gold nanoshells, or magnetic nanoparticles at laser energies that are safe for humans. In addition, a photoacoustic (PA) effect was used to control nanoparticle delivery. Through the integration of this technique with molecular targeting, nanoparticle clustering, magnetic capturing and spectral sharpening of PA and PT plasmonic resonances, our laser-based PA-PT nano-theranostic platform can be applied to detection and the physical destruction of small organisms and carriers of pathogens, such as malaria vectors, spiders, bed bugs, fleas, ants, locusts, grasshoppers, phytophagous mites, or other arthropod pests, irrespective of their resistance to conventional treatments.
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Affiliation(s)
- Stephen R Foster
- Phillips Classic Laser and Nanomedicine Laboratories, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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Ndiath MO, Mazenot C, Sokhna C, Trape JF. How the malaria vector Anopheles gambiae adapts to the use of insecticide-treated nets by African populations. PLoS One 2014; 9:e97700. [PMID: 24892677 PMCID: PMC4043680 DOI: 10.1371/journal.pone.0097700] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/23/2014] [Indexed: 11/18/2022] Open
Abstract
Background Insecticide treated bed nets have been recommended and proven efficient as a measure to protect African populations from malaria mosquito vector Anopheles spp. This study evaluates the consequences of bed nets use on vectors resistance to insecticides, their feeding behavior and malaria transmission in Dielmo village, Senegal, were LLINs were offered to all villagers in July 2008. Methods Adult mosquitoes were collected monthly from January 2006 to December 2011 by human landing catches (HLC) and by pyrethroid spray catches (PCS). A randomly selected sub-sample of 15–20% of An. gambiae s.l. collected each month was used to investigate the molecular forms of the An. gambiae complex, kdr mutations, and Plasmodium falciparum circumsporozoite (CSP) rate. Malaria prevalence and gametocytaemia in Dielmo villagers were measured quarterly. Results Insecticide susceptible mosquitoes (wild kdr genotype) presented a reduced lifespan after LLINs implementation but they rapidly adapted their feeding behavior, becoming more exophageous and zoophilic, and biting earlier during the night. In the meantime, insecticide-resistant specimens (kdr L1014F genotype) increased in frequency in the population, with an unchanged lifespan and feeding behaviour. P. falciparum prevalence and gametocyte rate in villagers decreased dramatically after LLINs deployment. Malaria infection rate tended to zero in susceptible mosquitoes whereas the infection rate increased markedly in the kdr homozygote mosquitoes. Conclusion Dramatic changes in vector populations and their behavior occurred after the deployment of LLINs due to the extraordinary adaptative skills of An. gambiae s. l. mosquitoes. However, despite the increasing proportion of insecticide resistant mosquitoes and their almost exclusive responsibility in malaria transmission, the P. falciparum gametocyte reservoir continued to decrease three years after the deployment of LLINs.
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Affiliation(s)
- Mamadou Ousmane Ndiath
- G4-Group, Institut Pasteur International Network, Entomology Unit, Institut Pasteur of Bangui, Bangui, Central African Republic
- * E-mail:
| | - Catherine Mazenot
- Laboratoire de Paludologie et de Zoologie Médicale, Institut de Recherche pour le Développement, Campus International UCAD- IRD, Hann, Dakar, Sénégal
| | - Cheikh Sokhna
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, Dakar, Sénégal
| | - Jean-François Trape
- Laboratoire de Paludologie et de Zoologie Médicale, Institut de Recherche pour le Développement, Campus International UCAD- IRD, Hann, Dakar, Sénégal
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Li Y, Shi X, Zhang Q, Hu J, Chen J, Wang W. Computational evidence for the detoxifying mechanism of epsilon class glutathione transferase toward the insecticide DDT. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:5008-5016. [PMID: 24678828 DOI: 10.1021/es405230j] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A combined quantum mechanics/molecular mechanics (QM/MM) computation of the detoxifying mechanism of an epsilon class glutathione transferases (GSTs) toward organochlorine insecticide DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, has been carried out. The exponential average barrier of the proton transfer mechanism is 15.2 kcal/mol, which is 27.6 kcal/mol lower than that of the GS-DDT conjugant mechanism. It suggests that the detoxifying reaction proceeds via a proton transfer mechanism where GSH acts as a cofactor rather than a conjugate. The study reveals that the protein environment has a strong effect on the reaction barrier. The experimentally proposed residues Arg112, Glu116 and Phe120 were found to have a strong influence on the detoxifying reaction. The influence of residues Pro13, Cys15, His53, Ile55, Glu67, Ser68, Phe115, and Leu119 was detected as well. It is worth noticing that Ile55 facilitates the detoxifying reaction most. On the basis of the structure of DDT, structure 2, (BrC6H4)2CHCCl3, is the best candidate among all the tested structures in resisting the detoxification of enzyme agGSTe2.
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Affiliation(s)
- Yanwei Li
- Environment Research Institute, Shandong University , Jinan 250100, P. R. China
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Chang X, Zhong D, Fang Q, Hartsel J, Zhou G, Shi L, Fang F, Zhu C, Yan G. Multiple resistances and complex mechanisms of Anopheles sinensis mosquito: a major obstacle to mosquito-borne diseases control and elimination in China. PLoS Negl Trop Dis 2014; 8:e2889. [PMID: 24852174 PMCID: PMC4031067 DOI: 10.1371/journal.pntd.0002889] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/10/2014] [Indexed: 11/19/2022] Open
Abstract
Malaria, dengue fever, and filariasis are three of the most common mosquito-borne diseases worldwide. Malaria and lymphatic filariasis can occur as concomitant human infections while also sharing common mosquito vectors. The overall prevalence and health significance of malaria and filariasis have made them top priorities for global elimination and control programmes. Pyrethroid resistance in anopheline mosquito vectors represents a highly significant problem to malaria control worldwide. Several methods have been proposed to mitigate insecticide resistance, including rotational use of insecticides with different modes of action. Anopheles sinensis, an important malaria and filariasis vector in Southeast Asia, represents an interesting mosquito species for examining the consequences of long-term insecticide rotation use on resistance. We examined insecticide resistance in two An. Sinensis populations from central and southern China against pyrethroids, organochlorines, organophosphates, and carbamates, which are the major classes of insecticides recommended for indoor residual spray. We found that the mosquito populations were highly resistant to the four classes of insecticides. High frequency of kdr mutation was revealed in the central population, whereas no kdr mutation was detected in the southern population. The frequency of G119S mutation in the ace-1 gene was moderate in both populations. The classification and regression trees (CART) statistical analysis found that metabolic detoxification was the most important resistance mechanism, whereas target site insensitivity of L1014 kdr mutation played a less important role. Our results indicate that metabolic detoxification was the dominant mechanism of resistance compared to target site insensitivity, and suggests that long-term rotational use of various insecticides has led An. sinensis to evolve a high insecticide resistance. This study highlights the complex network of mechanisms conferring multiple resistances to chemical insecticides in mosquito vectors and it has important implication for designing and implementing vector resistance management strategies.
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Affiliation(s)
- Xuelian Chang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
- Department of Pathogen Biology, Bengbu Medical College, Anhui, China
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Qiang Fang
- Department of Pathogen Biology, Bengbu Medical College, Anhui, China
| | - Joshua Hartsel
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
| | - Linna Shi
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Fujin Fang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Changliang Zhu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, China
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, California, United States of America
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Sougoufara S, Diédhiou SM, Doucouré S, Diagne N, Sembène PM, Harry M, Trape JF, Sokhna C, Ndiath MO. Biting by Anopheles funestus in broad daylight after use of long-lasting insecticidal nets: a new challenge to malaria elimination. Malar J 2014; 13:125. [PMID: 24678587 PMCID: PMC3973838 DOI: 10.1186/1475-2875-13-125] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 03/25/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria control is mainly based on indoor residual spraying and insecticide-treated bed nets. The efficacy of these tools depends on the behaviour of mosquitoes, which varies by species. With resistance to insecticides, mosquitoes adapt their behaviour to ensure their survival and reproduction. The aim of this study was to assess the biting behaviour of Anopheles funestus after the implementation of long-lasting insecticidal nets (LLINs). METHODS A study was conducted in Dielmo, a rural Senegalese village, after a second massive deployment of LLINs in July 2011. Adult mosquitoes were collected by human landing catch and by pyrethrum spray catch monthly between July 2011 and April 2013. Anophelines were identified by stereomicroscope and sub-species by PCR. The presence of circumsporozoite protein of Plasmodium falciparum and the blood meal origin were detected by ELISA. RESULTS Anopheles funestus showed a behavioural change in biting activity after introduction of LLINs, remaining anthropophilic and endophilic, while adopting diurnal feeding, essentially on humans. Six times more An. funestus were captured in broad daylight than at night. Only one infected mosquito was found during day capture. The mean of day CSP rate was 1.28% while no positive An. funestus was found in night captures. CONCLUSION Mosquito behaviour is an essential component for assessing vectorial capacity to transmit malaria. The emergence of new behavioural patterns of mosquitoes may significantly increase the risk for malaria transmission and represents a new challenge for malaria control. Additional vector control strategies are, therefore, necessary.
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Affiliation(s)
- Seynabou Sougoufara
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, CP 18524 Dakar, Sénégal
- Département de Biologie Animale, FST/UCAD, BP 5005 Dakar Fann, Sénégal
| | - Seynabou Mocote Diédhiou
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, CP 18524 Dakar, Sénégal
- Département de Biologie Animale, FST/UCAD, BP 5005 Dakar Fann, Sénégal
| | - Souleymane Doucouré
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, CP 18524 Dakar, Sénégal
| | - Nafissatou Diagne
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, CP 18524 Dakar, Sénégal
| | | | - Myriam Harry
- Laboratoire Evolution, Génomes et Spéciation, Université Paris-Sud 11, 91198 Gif-sur-Yvette, Cedex, France
| | - Jean-François Trape
- Laboratoire de Paludologie, Campus International UCAD-IRD Hann, BP 1386 CP 18524 Dakar, Sénégal
| | - Cheikh Sokhna
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, IRD198, UM63, CNRS7278, INSERMU1095, Aix-Marseille Université, Campus UCAD-IRD, BP 1386, CP 18524 Dakar, Sénégal
| | - Mamadou Ousmane Ndiath
- Laboratoire de Paludologie, Campus International UCAD-IRD Hann, BP 1386 CP 18524 Dakar, Sénégal
- G4 International Group, Institut Pasteur International Network, Entomology Unit, Institute Pasteur of Bangui, BP 926 Bangui, Central African Republic
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The impact of pyrethroid resistance on the efficacy of insecticide-treated bed nets against African anopheline mosquitoes: systematic review and meta-analysis. PLoS Med 2014; 11:e1001619. [PMID: 24642791 PMCID: PMC3958359 DOI: 10.1371/journal.pmed.1001619] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 02/06/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Pyrethroid insecticide-treated bed nets (ITNs) help contribute to reducing malaria deaths in Africa, but their efficacy is threatened by insecticide resistance in some malaria mosquito vectors. We therefore assessed the evidence that resistance is attenuating the effect of ITNs on entomological outcomes. METHODS AND FINDINGS We included laboratory and field studies of African malaria vectors that measured resistance at the time of the study and used World Health Organization-recommended impregnation regimens. We reported mosquito mortality, blood feeding, induced exophily (premature exit of mosquitoes from the hut), deterrence, time to 50% or 95% knock-down, and percentage knock-down at 60 min. Publications were searched from 1 January 1980 to 31 December 2013 using MEDLINE, Cochrane Central Register of Controlled Trials, Science Citation Index Expanded, Social Sciences Citation Index, African Index Medicus, and CAB Abstracts. We stratified studies into three levels of insecticide resistance, and ITNs were compared with untreated bed nets (UTNs) using the risk difference (RD). Heterogeneity was explored visually and statistically. Included were 36 laboratory and 24 field studies, reported in 25 records. Studies tested and reported resistance inconsistently. Based on the meta-analytic results, the difference in mosquito mortality risk for ITNs compared to UTNs was lower in higher resistance categories. However, mortality risk was significantly higher for ITNs compared to UTNs regardless of resistance. For cone tests: low resistance, risk difference (RD) 0.86 (95% CI 0.72 to 1.01); moderate resistance, RD 0.71 (95% CI 0.53 to 0.88); high resistance, RD 0.56 (95% CI 0.17 to 0.95). For tunnel tests: low resistance, RD 0.74 (95% CI 0.61 to 0.87); moderate resistance, RD 0.50 (95% CI 0.40 to 0.60); high resistance, RD 0.39 (95% CI 0.24 to 0.54). For hut studies: low resistance, RD 0.56 (95% CI 0.43 to 0.68); moderate resistance, RD 0.39 (95% CI 0.16 to 0.61); high resistance, RD 0.35 (95% CI 0.27 to 0.43). However, with the exception of the moderate resistance category for tunnel tests, there was extremely high heterogeneity across studies in each resistance category (chi-squared test, p<0.00001, I² varied from 95% to 100%). CONCLUSIONS This meta-analysis found that ITNs are more effective than UTNs regardless of resistance. There appears to be a relationship between resistance and the RD for mosquito mortality in laboratory and field studies. However, the substantive heterogeneity in the studies' results and design may mask the true relationship between resistance and the RD, and the results need to be interpreted with caution. Our analysis suggests the potential for cumulative meta-analysis in entomological trials, but further field research in this area will require specialists in the field to work together to improve the quality of trials, and to standardise designs, assessment, and reporting of both resistance and entomological outcomes.
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Lol JC, Castellanos ME, Liebman KA, Lenhart A, Pennington PM, Padilla NR. Molecular evidence for historical presence of knock-down resistance in Anopheles albimanus, a key malaria vector in Latin America. Parasit Vectors 2013; 6:268. [PMID: 24330978 PMCID: PMC3848997 DOI: 10.1186/1756-3305-6-268] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/12/2013] [Indexed: 11/22/2022] Open
Abstract
Background Anopheles albimanus is a key malaria vector in the northern neotropics. Current vector control measures in the region are based on mass distributions of long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) with pyrethroids. Resistance to pyrethroid insecticides can be mediated by increased esterase and/or multi-function oxidase activity and/or mutations in the voltage-gated sodium channel gene. The aim of this work was to characterize the homologous kdr region of the voltage-gated sodium channel gene in An. albimanus and to conduct a preliminary retrospective analysis of field samples collected in the 1990’s, coinciding with a time of intense pyrethroid application related to agricultural and public health insect control in the region. Methods Degenerate primers were designed to amplify the homologous kdr region in a pyrethroid-susceptible laboratory strain (Sanarate) of An. albimanus. Subsequently, a more specific primer pair was used to amplify and sequence the region that contains the 1014 codon associated with pyrethroid resistance in other Anopheles spp. (L1014F, L1014S or L1014C). Results Direct sequencing of the PCR products confirmed the presence of the susceptible kdr allele in the Sanarate strain (L1014) and the presence of homozygous-resistant kdr alleles in field-collected individuals from Mexico (L1014F), Nicaragua (L1014C) and Costa Rica (L1014C). Conclusions For the first time, the kdr region in An. albimanus is described. Furthermore, molecular evidence suggests the presence of kdr-type resistance in field-collected An. albimanus in Mesoamerica in the 1990s. Further research is needed to conclusively determine an association between the genotypes and resistant phenotypes, and to what extent they may compromise current vector control efforts.
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Tangena JAA, Adiamoh M, D’Alessandro U, Jarju L, Jawara M, Jeffries D, Malik N, Nwakanma D, Kaur H, Takken W, Lindsay SW, Pinder M. Alternative treatments for indoor residual spraying for malaria control in a village with pyrethroid- and DDT-resistant vectors in the Gambia. PLoS One 2013; 8:e74351. [PMID: 24058551 PMCID: PMC3772946 DOI: 10.1371/journal.pone.0074351] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Accepted: 07/31/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Malaria vector control is threatened by resistance to pyrethroids, the only class of insecticides used for treating bed nets. The second major vector control method is indoor residual spraying with pyrethroids or the organochloride DDT. However, resistance to pyrethroids frequently confers resistance to DDT. Therefore, alternative insecticides are urgently needed. METHODOLOGY/PRINCIPAL FINDINGS Insecticide resistance and the efficacy of indoor residual spraying with different insecticides was determined in a Gambian village. Resistance of local vectors to pyrethroids and DDT was high (31% and 46% mortality, respectively) while resistance to bendiocarb and pirimiphos methyl was low (88% and 100% mortality, respectively). The vectors were predominantly Anopheles gambiae s.s. with 94% of them having the putative resistant genotype kdr 1014F. Four groups of eight residential compounds were each sprayed with either (1) bendiocarb, a carbamate, (2) DDT, an organochlorine, (3) microencapsulated pirimiphos methyl, an organophosphate, or (4) left unsprayed. All insecticides tested showed high residual activity up to five months after application. Mosquito house entry, estimated by light traps, was similar in all houses with metal roofs, but was significantly less in IRS houses with thatched roofs (p=0.02). Residents participating in focus group discussions indicated that IRS was considered a necessary nuisance and also may decrease the use of long-lasting insecticidal nets. CONCLUSION/SIGNIFICANCE Bendiocarb and microencapsulated pirimiphos methyl are viable alternatives for indoor residual spraying where resistance to pyrethroids and DDT is high and may assist in the management of pyrethroid resistance.
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Affiliation(s)
- Julie-Anne A. Tangena
- Laboratory of Entomology, Wageningen University and Research Centre, EH Wageningen, Netherlands
- Institut Pasteur du Laos, Vientiane, Lao PDR
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom
| | - Majidah Adiamoh
- Disease Control and Elimination Theme, Medical Research Council Unit, Banjul, Gambia
| | - Umberto D’Alessandro
- Disease Control and Elimination Theme, Medical Research Council Unit, Banjul, Gambia
- Unit of Malariology, Institute of Tropical Medicine, Antwerp, Belgium
| | - Lamin Jarju
- National Malaria Control Programme, Kanifing, Gambia
| | - Musa Jawara
- Disease Control and Elimination Theme, Medical Research Council Unit, Banjul, Gambia
| | - David Jeffries
- Statistics, Medical Research Council Unit, Banjul, Gambia
| | - Naiela Malik
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Davis Nwakanma
- Disease Control and Elimination Theme, Medical Research Council Unit, Banjul, Gambia
| | - Harparkash Kaur
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research Centre, EH Wageningen, Netherlands
| | - Steve W. Lindsay
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom
| | - Margaret Pinder
- Disease Control and Elimination Theme, Medical Research Council Unit, Banjul, Gambia
- London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom
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Massebo F, Balkew M, Gebre-Michael T, Lindtjørn B. Blood meal origins and insecticide susceptibility of Anopheles arabiensis from Chano in South-West Ethiopia. Parasit Vectors 2013; 6:44. [PMID: 23433306 PMCID: PMC3606335 DOI: 10.1186/1756-3305-6-44] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 02/19/2013] [Indexed: 11/29/2022] Open
Abstract
Background Anopheles arabiensis, the main malaria vector in Ethiopia, shows both anthropophilic and zoophilic behaviours. Insecticide resistance is increasing, and alternative methods of vector control are needed. The objectives of this study were to determine the blood meal origins and the susceptibility to insecticides of An. arabiensis from Chano village near Arba Minch in South-West Ethiopia. Methods Blood meal sources of anopheline mosquitoes collected using Centers for Disease Control and Prevention (CDC) light traps and pyrethrum spray catches (PSC) from human dwellings, and hand-held mouth aspirators from outdoor pit shelters were analysed using a direct enzyme-linked-immunosorbent assay (ELISA). The susceptibility of An. arabiensis to pyrethroid insecticides (alphacypermethrin, lambdacyhalothrin, deltamethrin, and cyfluthrin) and DDT was assessed using females reared from larval and pupal collections from natural breeding sites. Results The blood meal origins of 2967 freshly fed Anopheles mosquitoes were determined. An. arabiensis was the predominant species (75%), and it fed mainly on cattle. The densities of both freshly fed An. arabiensis and those fed on human blood followed similar seasonal patterns. The overall human blood index (HBI) of An. arabiensis, including mixed blood meals, was 44% and the bovine blood index (BBI) was 69%. The HBI of An. arabiensis from CDC light trap collections was 75% and this was higher than those for PSC (38%) and outdoor pit shelter collections (13%), while the BBI was 65% for PSC, 68% for outdoor pit shelters and 72% for CDC light traps. More freshly fed and human blood-fed An. arabiensis were sampled from houses close to the shore of Lake Abaya (the major breeding site). A high proportion of An. arabiensis was resistant to the pyrethroid insecticides, with a mortality rate of 56% for lambdacyhalothrin, 50% for cyfluthrin and alphacypermethrin, 47% for deltamethrin, and 10% for DDT. Conclusion Anopheles arabiensis is the predominant species of anopheline mosquito in this region, and cattle are the main source of its blood meals. The greater tendency of this species to feed on cattle justifies the application of insecticides on cattle to control it. However, An. arabiensis has already developed resistance to the available pyrethroid insecticides, and alternative insecticides are needed for malaria vector control.
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Affiliation(s)
- Fekadu Massebo
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia.
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O'Neal MA, Posner BA, Coates CJ, Abrams JM. A cell-based screening platform identifies novel mosquitocidal toxins. ACTA ACUST UNITED AC 2013; 18:688-94. [PMID: 23407365 DOI: 10.1177/1087057113476952] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Pesticides currently in widespread use often lack species specificity and also become less effective as resistance emerges. Consequently, there is a pressing need to develop novel agents that are narrowly targeted and safe to humans. A cell-based screening platform was designed to discover compounds that are lethal to mosquito (Anopheles and Aedes) cells but show little or no activity against other insect (Drosophila) or human cell lines. Mosquito-specific, aqueous-stable cytotoxins were recovered at rare frequencies. Three of these were profiled for structure-activity relationships and also assessed in whole-animal toxicity assays. In at least one test case, species-specific cytotoxicity seen in culture effectively translated to the whole-animal level, with potent toxicity against Anopheles yet none against Drosophila. Therefore, this initiative has the potential to advance novel mosquitocidal agents and, in a broader sense, could establish a versatile platform for developing customized pesticides that selectively target other disease vectors as well.
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Affiliation(s)
- Melissa A O'Neal
- University of Texas Southwestern Medical Center, Department of Cell Biology, Dallas, TX, USA
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36
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Jagannathan P, Muhindo MK, Kakuru A, Arinaitwe E, Greenhouse B, Tappero J, Rosenthal PJ, Kaharuza F, Kamya MR, Dorsey G. Increasing incidence of malaria in children despite insecticide-treated bed nets and prompt anti-malarial therapy in Tororo, Uganda. Malar J 2012; 11:435. [PMID: 23273022 PMCID: PMC3551700 DOI: 10.1186/1475-2875-11-435] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 12/26/2012] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The burden of malaria has decreased in parts of Africa following the scaling up of control interventions. However, similar data are limited from high transmission settings. METHODS A cohort of 100 children, aged six weeks to 10 months of age, were enrolled in an area of high malaria transmission intensity and followed through 48 months of age. Children were given a long-lasting insecticide-treated bed net (LLIN) at enrolment and received all care, including monthly blood smears and treatment with artemisinin-based combination therapy (ACT) for uncomplicated malaria, at a dedicated clinic. The incidence of malaria was estimated by passive surveillance and associations between malaria incidence and age, calendar time and season were measured using generalized estimating equations. RESULTS Reported compliance with LLINs was 98% based on monthly routine evaluations. A total of 1,633 episodes of malaria were observed, with a median incidence of 5.3 per person-year (PPY). There were only six cases of complicated malaria, all single convulsions. Malaria incidence peaked at 6.5 PPY at 23 months of age before declining to 3.5 PPY at 48 months. After adjusting for age and season, the risk of malaria increased by 52% from 2008 to 2011 (RR 1.52, 95% CI 1.10-2.09). Asymptomatic parasitaemia was uncommon (monthly prevalence <10%) and rarely observed prior to 24 months of age. CONCLUSIONS In Tororo, despite provision of LLINs and prompt treatment with ACT, the incidence of malaria is very high and appears to be rising. Additional malaria control interventions in high transmission settings are likely needed. TRIAL REGISTRATION Current Controlled Trials Identifier NCT00527800.
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Affiliation(s)
- Prasanna Jagannathan
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, CA, USA
| | - Mary K Muhindo
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Abel Kakuru
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | - Bryan Greenhouse
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, CA, USA
| | - Jordan Tappero
- Global AIDS Program, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Philip J Rosenthal
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, CA, USA
| | - Frank Kaharuza
- Centers for Disease Control and Prevention, Kampala, Uganda
| | - Moses R Kamya
- Department of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, CA, USA
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Dell’Agli M, Sanna C, Rubiolo P, Basilico N, Colombo E, Scaltrito MM, Ndiath MO, Maccarone L, Taramelli D, Bicchi C, Ballero M, Bosisio E. Anti-plasmodial and insecticidal activities of the essential oils of aromatic plants growing in the Mediterranean area. Malar J 2012; 11:219. [PMID: 22747579 PMCID: PMC3441327 DOI: 10.1186/1475-2875-11-219] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 06/19/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sardinia is a Mediterranean area endemic for malaria up to the last century. During a screening study to evaluate the anti-plasmodial activity of some aromatic plants traditionally used in Sardinia, Myrtus communis (myrtle, Myrtaceae), Satureja thymbra (savory, Lamiaceae), and Thymus herba-barona (caraway thyme, Lamiaceae) were collected in three vegetative periods: before, during and after flowering. METHODS The essential oils were obtained by steam distillation, fractionated by silica gel column chromatography and analysed by GC-FID-MS. Total oil and three main fractions were tested on D10 and W2 strains of Plasmodium falciparum in vitro. Larvicidal and adulticidal activities were tested on Anopheles gambiae susceptible strains. RESULTS The essential oil of savory, rich in thymol, was the most effective against P. falciparum with an inhibitory activity independent from the time of collection (IC50 17-26 μg/ml on D10 and 9-11 μg/ml on W2). Upon fractionation, fraction 1 was enriched in mono-sesquiterpenoid hydrocarbons; fraction 2 in thymol (73-83%); and fraction 3 contained thymol, carvacrol and terpinen-4-ol, with a different composition depending on the time of collection. Thymol-enriched fractions were the most active on both strains (IC50 20-22 μg/ml on D10 and 8-10 μg/ml on W2) and thymol was confirmed as mainly responsible for this activity (IC50 19.7 ± 3.0 and 10.6 ± 2.0 μg/ml on D10 and W2, respectively). The essential oil of S. thymbra L. showed also larvicidal and adulticidal activities. The larvicidal activity, expressed as LC50, was 0.15 ± 0.002; 0.21 ± 0.13; and 0.15 ± 0.09 μg/ml (mean ± sd) depending on the time of collection: before, during and after flowering, respectively. CONCLUSIONS This study provides evidence for the use of essential oils for treating malaria and fighting the vector at both the larval and adult stages. These findings open the possibility for further investigation aimed at the isolation of natural products with anti-parasitic properties.
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Affiliation(s)
- Mario Dell’Agli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Cinzia Sanna
- Co.S.Me.Se, Dipartimento di Scienze della Vita e dell’Ambiente, Macrosezione Botanica e Orto botanico, Università degli Studi di Cagliari, Cagliari, Italy
| | - Patrizia Rubiolo
- Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Torino, Italy
| | - Nicoletta Basilico
- Dipartimento di Scienze biomediche, chirurgiche e odontoiatriche, Università degli Studi di Milano, Milan, Italy
| | - Elisa Colombo
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Maria M Scaltrito
- Dipartimento di Scienze biomediche, chirurgiche e odontoiatriche, Università degli Studi di Milano, Milan, Italy
| | | | - Luca Maccarone
- Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Torino, Italy
| | - Donatella Taramelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Carlo Bicchi
- Dipartimento di Scienza e Tecnologia del Farmaco, Università degli Studi di Torino, Torino, Italy
| | - Mauro Ballero
- Co.S.Me.Se, Dipartimento di Scienze della Vita e dell’Ambiente, Macrosezione Botanica e Orto botanico, Università degli Studi di Cagliari, Cagliari, Italy
| | - Enrica Bosisio
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
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